Accuracy of the spin sum rule in XMCD for the transition-metalLedges from manganese to copper

Abstract

The effective spin sum rule is widely used in the quantitative analysis of x-ray magnetic circular dichroism spectra. Here, this important, though imperfect, sum rule is reviewed with a detailed analysis of the various sources for errors and deviations. The simulations confirm that the final state effects of the core level spin-orbit coupling and the core-valence exchange interactions ͑multiplet effects͒ are linearly related with the effective spin sum-rule error. Within the charge transfer multiplet approach, we have analyzed these effects, in combination with the interactions affecting the magnetic ground state, including the crystal field strength, the charge transfer effects, the exchange ͑magnetic͒ field, and the 3d spin-orbit coupling. We find that for the late transition-metal systems, the error in the effective spin moment is between 5% and 10%, implying that for covalent and/or metallic systems the effective spin sum rule is precise to within 5-10 %. The error for 3d 5 systems is ϳ30% and for 3d 4 systems, the error is very large, implying that, without further information, the derived effective spin sum-rule values for 3d 4 systems have no meaning.

Ferromagnetism and ferroelectricity in epitaxial BiMnO3 ultra-thin films

“…This correction factor is necessary, since it is known that the sum rules do not apply exactly to Mn. 15 In Fig. 3, we show the magnetization, measured from 9 K to room temperature, in a magnetic field of 2 T. Both strained and unstrained BMO show a ferromagnetic transition around T C ¼ 100 K, which is similar to the well known bulk value.…”

Intra- and interparticle magnetism of cobalt-doped iron-oxide nanoparticles encapsulated in a synthetic ferritin cage

“…Since s-states are not relevant to the calculation of m l /m s , the integral was terminated at the point where there was no longer a slope in the XMCD intensity (799 eV). For this reason, and since it known that there are limitations to the validity of the sum rules for transition metal oxides, for example, due to mixing of the L 2 and L 3 edges that can result in a large discrepancy in the derived magnetic moments 26 , we compare only the relative change in m l /m s between samples, having applied the same integration procedure to all spectra. No significant deviation from the expected m l /m s = 0 for spinel oxides was observed for all of the Fe spectra for all samples.…”

Ubiquitous long-range antiferromagnetic coupling across the interface between superconducting and ferromagnetic oxides

“…It is negative for small magnetic fields, and positive for large fields vanishing at fields of the order of 2 T, in fair agreement with XMCD data (see also Supplementary Figs 11 and 12). The comparison with the experimental data (red squares) obtained with the sum rules 23,24,34 can be used to quantify the value of J A . For LSCO coupled to LSMO (interface B), we have found J A E0.15 t, four times smaller than what was estimated in previous experiments for YBCO 31 .…”